A cylinder of length l, has a constant magnetic field B inside it, which is perpendicular to the cylinder axis. An electron of charge -e and mass m enters the cylinder with velocity v along the cylinder axis. If the radius of the cylinder is r = mveB, which of the following ensures that the electron leaves the cylinder with a velocity along the cylinder axis?

Consider a production line with five stations. station 1 can produce a unit in 9 minutes. station 2 can produce a unit in 10 minutes. station 3 has two identical machines, each of which can process a unit in 12 minutes (each unit only needs to be processed on one of the two machines. station 4 can produce a unit in 5 minutes. station 5 can produce a unit in 8 minutes. which station is the bottleneck station?